Digital video can be transmitted from a source, such as a DVD player, video receiver, ATSC tuner, or other computer, to a display, such as a flat panel video monitor, using a protocol known as Digital Visual Interface (DVI). Having been developed primarily for computers, DVI does not envision processing audio data.
Accordingly, to extend communication protocols to digital multimedia that includes audio for the purpose of, e.g., playing digital movies and the like, a protocol referred to as High Definition Multimedia Interface (HDMI) has been developed. HDMI is similar to DVI except it envisions the use of audio as well as video data and it adds television-related resolutions. Both DVI and HDMI are intended for wired transmission, and HDMI further permits the encryption of digital multimedia using an encryption method known as High-Bandwidth Digital Content Protection (HDCP). DVI also supports HDCP as an optional characteristic.
As recognized herein, to save table space and to increase people's mobility and viewing lines in the room, it may be desirable to view the multimedia on a display using a minimum of wiring. For instance, it may be desirable to mount a projector on the ceiling or to mount a plasma display or liquid crystal high definition (HD) television display on a wall, out of the way and capable of receiving multimedia data for display without the need for wires, since as understood herein among other things data transmission lines often do not exist in ceilings or walls.
The present invention further understands, however, that not just any wireless transmission system will do. Specifically, if a wireless link such as IEEE 802.11(b) is used that has a bandwidth which is insufficient to carry either compressed or uncompressed multimedia such as uncompressed high definition (HD) video, compressed multimedia standard definition (SD) video would have to be transmitted, requiring a relatively expensive decompression module at the projector. Some links such as IEEE 802.11(a) do have a bandwidth high enough to carry compressed HD video but not uncompressed SD or HD video. Also, in the case of 802.11(a) copyright protection may be implicated because the link is sufficiently long range (extending beyond the room in which it originates) that it can be detected beyond the immediate location of the transmitting laptop. With this in mind, the present invention recognizes the need for a very short range, preferably directional, high bandwidth wireless link that is particularly suited for the short range wireless communication of uncompressed multimedia, particularly the rather voluminous genre of multimedia known as HD video.
The present assignee has provided a wireless system that functions in the spectrum between 57 GHz and 64 GHz (hereinafter “60 GHz band”). Characteristics of the 60 GHz spectrum include short range, high directivity (and, hence, inherent security), and large data bandwidth. The present assignee's co-pending U.S. patent application Ser. Nos. 10/666,724, 10/744,903 (systems), Ser. Nos. 10/893,819, 11/136,199 (PLL-related inventions), and Ser. No. 11/035,845 (multiple antennae), all of which are incorporated herein by reference, disclose various systems and methods for sending high definition (HD) video in High Definition Multimedia Interface (HDMI) format from a source in a room to a receiver in the room, using a high bandwidth 60 GHz link. At this frequency the signal has very short range and can be directional such that the video may be transmitted in an uncompressed form such that so much data is transmitted each second that bootlegging the content is essentially untenable.
Regardless of the particular application, the present invention makes the following critical observation about 60 GHz wireless links. As understood herein, simpler, non-audio DVI components are less expensive than HDMI components which add the feature of audio and, hence, would be desirable to use when feasible in lieu of HDMI components. Unfortunately, an HDMI transmitter will never send HDMI data to a DVI receiver once the transmitter discovers that the receiver is not HDMI, so it can be difficult to mix the two systems. Nonetheless, the present invention understands that it is possible to selectively use less expensive DVI components in an HDMI system.